(a) Field of the Invention
The present invention relates to a self-supporting flexible wall dam. It deals with a flexible wall dam, vertically supported by the upward vertical component of the internal water pressure acting on it and it balances and counterbalances the horizontal water pressure acting on it.
(b)Description of Prior Art
French Patent No. 495,788 issued to L. Debarle teaches a flexible membrane dam for irrigation canals consisting of a canvas or a simple flexible membrane dam with the lower edge of the said membrane buried in a trench and covered with earth as a means of anchoring. Debarle uses random anchoring ties and floats together with vertical solid posts to support the flexible membrane assembly and the downward pulling forces generated by the random anchoring ties.
U.S.S.R. Patent No. 618,481 issued to Melior describes a water level control system which consists of a float connected to a vertical sliding gate by means of a rope. With the rise of the water level the float rises and lifts up the gate allowing the water to escape thereby keeping the water level under control. The Melior Patent is based on a float using the buoyancy water pressure which is different than the vertical component of the internal water pressure acting on the retaining flexible wall.
The actual prior art is applicable to water heads from 3 to 6 ft. high, beyond which, it becomes impractical, uneconomical and gradually impossible.
For example, consider a flexible wall dam retaining a water head 33 ft. high or 10 metres with two anchoring ties at 45.degree., one at 5 metres high and one at the top of the flexible wall at 10 metres from-the waterbed.
The approximate stresses on a vertical strip of the flexible wall, one metre wide or 3.3 ft. and 10 metres high due to the water pressure only are the following.
The horizontal water pressure at the anchoring line is over 7 ton per linear ft. The tension stress at the intersection of the middle anchoring cable with the flexible wall is over 35 tons. The vertical downward forces resulting from the 45.degree. anchoring cables are about 28 tons per linear metre and with the flexible wall and attachments, they would reach well over 30 tons per linear metre, which requires a continuous float of 5 metres deep by 6 metres wide, which is a costly additional installation that would require additional ties and connections with the flexible wall.
The actual material used for the flexible walls in the prior art could not stand loads of 7 tons per linear ft. at the anchoring lines. The flexible wall material available until now and used in the prior art could not stand 35 tons of tension stresses at the connection point of the middle anchoring cable and the flexible wall. The use of plain, random anchoring ties and floats to support the system becomes impractical, uneconomical and gradually impossible. In other words, it would be cheaper to build concrete dams rather than ties and floats nearly reaching the floor of the dam. The anchoring system used in the prior art, by covering the lower edge of the flexible wall with earth or gravel could in no way support 7 tons per linear ft. of horizontal water pressure, and in case bolts and nuts are used on the flexible wall, the 7 tons of tension stresses per linear ft. would tear up the flexible wall. Besides, the life span of the flexible walls, available up to date is from 20 to 30 years at the most, after which the flexible wall has to be fully or partially replaced.
For a flexible wall dam anchored under a mass of earth and for a flexible wall dam anchored through a bolt and nut system that becomes covered with rust and sediments, it would be necessary to dig up and rebuild the whole anchoring system every time the flexible wall has to be repaired or replaced.
The aforementioned example provides that the technology used in the prior art, either singly or in combination, and the material available until now for the flexible walls used in the prior art, are only good for low water heads of 3 to 6 ft. high for irrigation canals or the like, beyond which the prior art becomes impractical, uneconomical and gradually impossible.
A new technology to manufacture the required cross reinforced flexible walls and a new complicated technology for splicing said flexible walls are therefore required to provide a new type of flexible wall. It is also required to balance the supports and the anchoring ties of the flexible wall dams to avoid the production of downward vertical forces by the anchoring tie.
It is also required to counterbalance the horizontal forces acting on the upstream and downstream flexible walls to create an independent, continuous self-supporting flexible wall dam assembly that stands up by itself without the use of external vertical supports, such as floats, vertical posts, supporting cables or the like.
It is also required to provide a new anchoring system that could insure a tight and firm grip between the flexible wall and the watered without perforation of the flexible wall, with the least material possible and in a simple system easy to install and dismantle, with the minimum underwater operation possible.
According to the invention there is provided a cross reinforced, cross spliced self-supporting flexible wall dam which is vertically supported by the upward vertical component of the internal water pressure acting on it, and the horizontal water pressure acting on the flexible walls is balanced and counterbalanced to create a self-supporting assembly which uses a restricted changeable anchoring system firmly secured to the waterbed.
It is an object of the present invention to provide a self-supporting flexible wall dam and the like for restraining the flow of water which comprises two oppositely disposed cross reinforced flexible walls, water filling the space therebetween, their lower edges being firmly secured to the waterbed with a restricted changeable system, and their upper edges being inclined towards each other, with balanced inclination. The walls are reinforced and interconnected with counterbalancing ties to counterbalance the horizontal forces of the varying water pressure acting on the flexible walls while the vertical component of the internal water pressure supports the flexible walls and their attachments.
It is another object of the invention to provide a flexible wall dam with balanced horizontal cable beams supporting the flexible wall and transferring their loads to the waterbed through balanced anchoring ties, avoiding the generation of downward forces on the flexible wall.
It is another object of the invention to provide a flexible wall dam having a downstream flexible wall wherein the horizontal counterbalancing ties are connected at the top edge of the flexible wall, to points upstream which are at the same level or higher.
It is another object of the present invention to provide a flexible wall dam having a downstream flexible wall wherein the horizontal counterbalancing ties are connected at the top edge of the flexible wall, and the anchoring ties below the counterbalancing ties are connected to points upstream at the same level or higher.
It is another object of the invention to provide a flexible wall dam solid hinging anchoring ties with solid spacers therebetween, to allow the flexible dam to open and close in a pattern similar to the hood of a baby carriage.
It is another object of the present invention to provide a water retaining flexible wall assembly wherein the flexible wall is folded around horizontally, with a cable beam reinforcement, to form a closed, truncated cone like structure, resting on its larger base, filled with water, vertically supported by the water filling it, and also being provided with counterbalancing rings.
It is another object of the present invention to provide a flexible wall dam wherein the top edge of the flexible wall is folded down and anchored to the waterbed, and is inflated with water to form a closed envelope capable of retaining a water head on one side.
It is another object of the present invention to provide a flexible wall envelope holding internal stagnant water above freezing temperature, by means of flowing water circulating through separate conduits passing through the stagnant water.
It is another object of the present invention to provide a flexible wall dam having an anchoring system consisting of a solid transversal "C" shaped cross section channel, embedded in the waterbed with its narrow opening horizontally disposed and flush with the waterbed surface where the lower edge of the flexible wall is laid inside the channel, beyond which, are inserted, longitudinal wedging blocks that are forced to interlock and squeeze the flexible wall inside the channel.